104 NEW YORK STATE MUSEUM 



same lake (on the Schenectady quadrangle) many such overthrust 

 faults were observed; in one place three above each other. They 

 all dip southeast, mostly at an angle of about 25°. Others were 

 observed in the bed of Fish creek at Victory Mills and in road 

 metal pits. In one place, a road metal pit east of Saratoga lake, 

 the slickensides upon the thrust planes, and especially the direc- 

 tion of the slickenside scales, left no doubt that the upthrow, side 

 had moved from east to west upon that plane. Some of these 

 overthrust faults have clearly resulted from overturned folds 

 (fold thrusts). The upper leg is seen in such cases to have been 

 pushed westward beyond the lower. Some instructive examples 

 of this were seen about Saratoga lake, especially on Snake hill. 

 Most of these small faults run with the general strike (north- 

 northeast direction) of the beds or are strike faults ; some were, 

 however, observed which cut the beds obliquely, as one at Victory 

 Mills, striking N. 60° E. These deviations from the general north- 

 northeast direction are probably connected with local irregularities 

 in the general trend of the folds. 



While the throw of each of these overthrust faults is but small, 

 their accumulative effect, going from west to east, owing to their 

 great number and uniform direction of throw, must be quite 

 large. If we assume a throw of 6 inches for each fault and 

 that they are 20 feet apart, we obtain for the belt measured 

 from the foot of Willard mountain normal to the strike, with a 

 width of 10 miles, a compound throw of 1320 feet. The eft'ect 

 of this accumulative throw would be to bring progressively older 

 beds to the surface of the Saratoga plain as one goes east. It is 

 therefore possible that the position of the Normanskill belts to 

 the east of the Snake Hill belts is largely due to this effect of the 

 small numerous overthrust faults which might be termed '' pro- 

 gressive overthrustsf 



The interesting observations of Woodworth^ have shown that 

 faulting of '' repetitive " character is still going on in the shale 

 belts to the south of the Schuylerville quadrangle and possibly also 

 in the latter. These small faults have also the same northeast 

 strike and where observed, raise the eastern part above the west- 



^ Woodworth, J. B. Postglacial Faults of Eastern New York. N. Y. State 

 Mus. Bui. 107, p. 5, 1907. 



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